Device for pulsating a liquid in a comumn

ABSTRACT

In order to pulsate liquid in a column, the column is connected to both the suction side and the pressure side of a pump, via rotatable valve means which alternately connects the pressure side and the suction side of the pump to the column. The rotations of the valve and the pumping force and the flow capacity of the piping between the column and the pump primarily influence the amplitude and frequency of pulsations in the column. More than one valve may be connected to one column and more than one column can be connected to one valve. Preferred valve designs are disclosed, as are preferred fluid circuits incorporating surge tank means.

United States Patent [191 Fontein et al.

[ 1 March 6, 1973 DEVICE FOR PULSATING A LIQUID IN A COMUMN [75] Inventors: Freerk J. Fontein, Heerlen; Martinus Ploeg, Brunssum; Jacques Van Linden, Stein, all of Netherlands [73] Assignee: Stamicarbon N.V., Heerlen, Netherlands [22] Filed: Sept. 29, 1971 [21] Appl. No.: 184,815

[30] Foreign Application Priority Data Sept. 29, 1970 Netherlands ..70l4268 April 10, 1971 Netherlands ..7l04843 [52] US. Cl ..l37/568 [51] Int. Cl ..F04d 27/02 [58] Field of Search ..l37/565, 568

[56] References Cited UNITED STATES PATENTS 3,504,686 4/1970 Cooper et a]. ..l37/568 x F H1972 Beguiristain l37/565 4/1972 Chapman ..l37/568X [5 7 ABSTRACT In order to pulsate liquid in a column, the column is connected to both the suction side and the pressure side of a pump, via rotatable valve means which alternately connects the pressure side and the suction side of the pump to the column. The rotations of the valve and the pumping force and the flow capacity of the piping between the column and the pump primarily influence the amplitude and frequency of pulsations in the column. More than one valve may be connected to one column and more than one column can be connected to one valve, Preferred valve designs are dis closed, as are preferred fluid circuits incorporating surge tank means.

20 Claims, 8 Drawing Figures SHEET 2 OF 8 Fig. 2

PATH-MU 51373 3,719,204

7 SHEEI 50F 8 Fig. 5

PATENTEUHAR 61915 3,719,204

SHEET 80F 8- V 235 t) I a 2% Fig.6

DEVICE FOR PULSA'IING A LIQUID IN A COMUMN BACKGROUND OF THE INVENTION Various processes and apparatus for pulsating liquid in a column are shown and described in the following United States patents. (This is not an exclusive list.) U.S. Pat. No. 3,285,138 by Otten issued Nov. 15, 1966 U.S. Pat. No. 3,491,782 by Oele et a1. issued Jan. 27, 1970 U.S. Pat. No. 3,499,752 by Vermijs issued Mar. 10, 1970 Ser. No. 118,344 by Van Koppen issued filed Feb. 24, 1971).

In those instances, pulsation in the column is shown effected by reciprocation or periodic inflation/deflation of a pulsation inducting device.

Such columns may be used, for example, to bring a dispersed liquid phase into contact with another liquid phase, for example, for purposes as extraction or washing of said first dispersed liquid. Other processes may be carried out in such a column, for example, chemical reactions between two liquid phases.

Pulsating devices using a pump circuit and a rotary valve as pulsator, whereby the pump circuit is filled with one of the column liquids are known from the British Pat. No. 995,767.

To obtain a high working degree of a pulsating column, it is necessary that both half periods of a full pulsating stroke are effective. This means that during the second half period of the full pulsating stroke the speed of the liquid in the column must be negative with respect to the average speed of the liquid through the column.

This cannot be accomplished with the device as described in British Pat. No. 995,767, wherein during the one-half period of the full pulsation the speed of the liquid column may be highly positive but during the other half period not less than zero. Therefore, the efficiency of such a column must be lower than that in a column wherein the pulsations are effected with a device according to the present invention.

U.S. Pat. No. 2,011,186 (van Dijck) shows an alternative of the apparatus of the above-mentioned British patent, using a piston-pump in the supply line of one of the liquids. Although with this device a negative speed of the liquid in a column may be obtained, this negative speed of the liquid is hard to accomplish in a column of large diameter with the piston pump. Columns of a diameter of several meters are under construction now. A piston with very large diameter or a very long and fast stroke would have to be used in connection with a column of such a size, and that is not considered practical.

SUMMARY OF THE INVENTION The construction and use of columns of large diameter have been made possible by using the device according to the invention.

Pulsation is effected in a column of liquid by communicating the liquid to a valve alternatingly connected, through rotation of the valve, to a source of pressure and a source of suction.

In order to pulsate liquid in a column, the column is connected to both the suction side and the pressure side of a pump, via a rotating valve which alternately connects the pressure side and the suction side of the pump to the column. The valve rotation speed and the pumping force and the flow capacity of the piping between the column and the pump primarily influence the amplitude and frequency of pulsations in the column. More than one valve may be connected to one column and more than one column can be connected to one valve. Preferred valve designs are disclosed, as are preferred fluid circuits incorporating surge tank means.

The use of such a pump circuit and a rotary valve as pulsator is a simple solution from a design point of view, is economic in energy consumption and, further, is compact. In addition, from the point of view of sealing, a rotary movement is more attractive than a reciprocating movement of a piston, diaphragm or bellows, particularly in the case of sealing against explosive, aggressive or poisonous liquids under high pressure. For, it is possible to fill the pump circuit with one of the column liquids, which offers the possibility of working at increased pressure.

A rotary valve for the pulsation device may consist of a stationary cylindrical casing with two diametrically opposed connections for the pump circuit intermediate the ends of the casing and with a set of column connections near each end of the casing, and of a shaft which is rotatably mounted in the casing, to which shaft is attached a baffle of such a shape that rotation thereof results in the two connections of the pump circuit being alternately brought in liquid communication with the one and with the other column connection.

In the design described the shaft is subject to an alternative axial load, while the unilateral radial load occurs intermittently. Sometimes, application of the device in the case of a single pulsation column cannot be realized in a simple way. When these two points are objectionable, the rotary valve mechanism is made double, the valves close alternately and the one valve is incorporated in the suction line and the other in the delivery line of the pump circuit, a surge tank being installed between each valve and the pump.

The alternate closing of the rotary valve of the mechanism can be obtained if the two valves are coupled mechanically and, for instance, rotate around the same axis. By preference, the two valves are installed on the same shaft and have a common connection to the pulsation column.

With a view to balancing, this common column connection is placed co-axially with the shaft, the shaft being given a vertical disposition.

According to one mode of realization, to which the invention is not limited, the valve mechanism may be provided with a vertically positioned, cylindrical casing; the column connection extends coaxially with the casing, which, at the bottom, is sealed by a wall through which a shaft end protrudes on which a valve is installed consisting of two radial wings, provided at their ends with a curved baffle placed concentrically with the casing and extending over approximately and the casing has four openings regularly distributed over the circumference and each extending over an angle of about 45 of the circumference, the opposite openings being connected to, respectively, the delivery side and the suction side of the pump through one or more surge vessels. Each of the openings may be connected to a surge vessel, but the opposite openings may also be connected in pairs to one surge vessel.

It is not absolutely necessary for the valves to close or open at the same moment; a small leakage stream during this procedure, at the expense of some pump capacity, is allowable, as is, therefore, some deviation of said angles of 135 and 45.

The principles of the invention will be further hereinafter discussed with reference to the drawings wherein preferred embodiments are shown. The specifics illustrated in the drawings are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of two pulsation columns with a common pulsation device according to the invention;

FIG. 2 is a longitudinal section of a rotary valve for use with the device according to the invention;

FIG. 3 is a cross-section along the line III-III of FIG. 2;

FIG. 4 is a schematic representation of a single column with a pulsation device according to the invention;

FIG. 5 is a schematic representation of a double valve-mechanism with one pulsation column and two air vessels;

FIG. 6 is a longitudinal section in one mode of realizing a rotary valve for use with the device according to FIG. 5, the valve mechanism being opened to two air vessels,

FIG. 7 is a cross-section according to section A-A in FIG. 6, the valve mechanism being closed to the air vessels, and

FIG. 8 is a perspective view of the lower side of a pulsation column provided with a device according to FIGS.6and 7.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS OF THE INVENTION FIG. 1 shows two pulsation columns, 1 and 2, which may each be provided for part of their length with a schematically represented packing, 3 and 4. Under and over the packing, there are collecting chambers 5 and 7 for the heavy phase and 6 and 8 for the light phase, respectively. The light phase is introduced at 9 and 11 and discharged at 13 and 15, while the heavy phase is introduced at and 12 and discharged at 14 and 16.

Each of the columns, 1 and 2, is in liquid communication with a rotary valve 19 via a connection 17 and 18, respectively. This rotary valve 19 is incorporated in a pump circuit 20 comprising a pump 21, which can be driven by a motor 22, a line 23 between the outlet of the pump 21 and the inlet of valve 19 and a line 24 between the outlet of the valve 19 and the inlet of the pump 21. The rotary valve 19 can be driven by a motor 25.

The valve 19 is shown in more detail in FIG. 2. The valve 19 consists of a cylindrical casing 26 shut off on both sides by a flange 27 and 28, the flanges being connected by tie rods 32. In the flanges 27 and 28, a shaft 29 is rotatably supported by bearings. In the wall of the cylindrical casing 26 a there are, in total, four connectio..s: two diametrically opposed connections 30 and 31 receiving the lines 23 and 24 of the pump circuit 20,

and two connections 33 and 34 located nearer to the flanges 27 and 28 and receiving the lines 17 and 18,

which lines communicate with the bottom of the columns 1 and 2, respectively.

On the shaft 29 of the valve 19 is mounted a baffle of such-shape that, on rotation of the shaft, the two connections 30 and 31 of the pump circuit 20 are alternately brought in liquid communication with the connection 33 to column 1 and the connection 34 to column 2, and vice versa.

The baffle may have the form of a flat plate with an elliptical outer circumference, which plate is attached obliquely to the shaft 29. This design is shown schematically in FIG. 1 and FIG. 4.

A design which is easier to realize from a technical point of view is shown in FIG. 2 and FIG. 3, the baffle being composed of two semi-circular plates 35 and 36, which are placed at right angles to the shaft 29 between the connections 33, 30 and 31 on the one hand and the connections 30, 31 and 34 on the other, and two rectangular plates 37 and 38, which on either side of the shaft 29 join up with the plates 35 and 36.

In order to avoid excessive pressure pulsations, each of the two rectangular plates 37 and 38 is provided at the end with a curved baffle 39 and 40, respectively, as a result of which the inlet and outlet holes 30 and 31 are made to close and open gradually, while at the same time short-circuiting of the pump circuit is avoided.

Of course, the shaft and baffle combination represent a rotatable valve plug and could, in instances where desired, to replaced by a more traditionally shaped valve plug having properly spatially disposed ports and port-interconnecting passageways.

The operation of the device according to the invention is described with reference to FIG. 1. The two phases move in countercurrent flow through the two columns 1 and 2. The two connecting lines 17 and 18, as well as the valve 19, and the remaining part of the pump circuit 20 are also filled with liquid. In view of the specific gravity, this liquid is preferably the heavy phase, but another liquid may be used just as well, provided it is heavier than the heavy phase and not miscible therewith. The pump 21 driven by the motor 22 is started simultaneously with the rotary valve 19, which is driven by the motor 25.

In the position of the valve 19, shown by acontinuous line in FIG. 1, liquid is forced from the pump circuit 20 through the line 23, the valve 19, and the connection 18 into the column 2, and simultaneously the same quantity of liquid is drawn from the column 1 through the connection 17, the valve 19, and the line 24 into the pump circuit 20. The valve 19 turns through and reaches the position which is shown by a dashed line in FIG. 1, in which position liquid is forced from the pump circuit 20 through the line 23, valve 19 and connection 17 into the column 1, and the same quantity of liquid is drawn from the column 2 through the connection 18, valve 19 and line 24 into the pump circuit 21).

In this way a pulsating movement is produced in both columns. The number of revolutions of the valve 19 is a direct measure of the frequency of the pulsations in the columns. The amplitude of the pulsations depends, among others, on the number of revolutions of the valve 19 and the capacity of the pump 21, while the shape of the pulsations is also determined by the shape of the curved baffles 39 and 40 (FIG. 3).

Of course, during the circulation of the liquid in the pump circuit 20, the temperature of this circulating liquid increases. In order to limit thistemperature increase, the casing 26 of the rotary valve 19 may be provided on the outside with cooling ribs.

In FIG. 1 two columns are connected to the pump circuit; if only one column is required, one of the columns may be replaced by, for example, an air vessel, e.g., a surge tank, (not shown in this figure). Another possibility, if only one column is used, is to connect one column connection of the rotary valve to the bottom of the column and the other column connection of the valve to the top of the column. This is shown in FIG. 4, liquid being pumped from pump circuit 120 through the rotary valve 119, either through connecting line 117 to the bottom of column 101 or through connection 118 to the top of column 101, an equivalent quantity of liquid being led through the other line from column 101 to the pump circuit.

In FIG. 5, 201 represents a pulsation column only the bottom of which is shown. The device for pulsating a liquid in column 201 comprises two rotary valves 202 and 203, two air vessels 204 and 205, and one pump 206, which, in the indicated manner, form the pump circuit which is connected to column 201. The two valves 202 and 203 are so designed that they open and close alternately.

When valve 203 is opened and valve 202 is closed, liquid flows from air vessel 205 to column 201, resulting in an upward pulsation stroke in column 201. When valve 203 closes, valve 202 opens and liquid fiows from column 201 to air vessel 204, bringing about a downward pulsation stroke in column 201. Since pump 206 continuously displaces liquid in the direction indicated by the arrows, surge vessel 205 will, when valve 203 is closed, be subject to overpressure as compared with column 201, while in surge vessel 204, when valve 202 is closed, there will be a vacuum as compared with column 201. Seeing that the frequency is rather high, for instance 150 pulsations a minute, the liquid level in vessels 204 and 205 fluctuates little.

The constructional example of the pulsation device is shown in the FIGS. 6, 7 and 8. The FIGS. 6 and 8 show the lower side of pulsation column 201 which is in liquid communication with the rotary valve through a column connection 222. The valve mechanism comprises a cylindrical casing 224 which is located co-axially with connection 222 and sealed, at the bottom, by a wall 225, through which a shaft end 226 protrudes. The shaft end 226 is supported on bearings outside the casing 224 and can be driven by means of a mechanism located outside the casing, which mechanism is not shown in detail. The shaft end 226 carries a hub 227 connected by means of two radial wings 228, to a cylindrical baffle 229, which baffle is provided with openings 230 in two opposite places, each of the openings extending over an angle of about 45 (FIG. 7). The cylindrical casing 224 is provided with four openings 231, distributed over the circumference, each The opposite openings 231 are connected to the of which also has a span of some 45. As a result of this 6 arrangement two opposite openings 231, open or close simultaneously when the shaft 226 rotates.

other two opposite holes, 231, are connected to the suction air vessels 233 in a similar way. At the bottom, the two sets of air vessels are connected to the delivery and the suction sides of a pump 241 (FIGS. 7 and 8) by means of the lines 238, 239, 240 and 235, 236, 237, respectively.

The opposite air vessels 233 and 234 according to FIG. 8 are connected, at the top, to a pressure-balancing line 242 and 243, respectively (FIG. 8).

Inside column 201, according to FIG. 6 a baffle 244 is installed near the bottom, which baffle, on the one hand, distributes the liquid jet entering the column over the column diameter, and, on the other, prevents particles from falling through connection 222, from column 201 into the valve mechanism.

When the installation is in operation the pump is put on stream simultaneously with the drive of valve 223. The pressure difference between the pressure air vessel(s) 205, or 234, and the suction air vessels 204 or 233, is practically equal at any time, the pressure in the air vessels varying at all times by only a few tenths of an atmosphere. As a result of this, the pump 241, virtually keeps to the same point of its characteristic and, hence, is liable to optimum dimensioning.

According to the drawings, the openings 230 and 231 are circular. If desired, they may have a different shape.

It should now be apparent that the pulsation column rotary valve device as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention hereinbefore. Because the pulsation column rotary valve device of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

What is claimed is:

1. A device for pulsating liquid in a column comprising:

a source of suction;

a source of pressure;

rotary valve means;

conduit means for communicating the valve means with the liquid in the column;

conduit means connecting the valve means with the source of suction;

conduit means connecting the valve means with the source of pressure;

said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for alternately communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and

means for rotating said rotary valve means plug means.

2. The liquid pulsating device of claim 1 wherein the valve comprises a housing including a cylindrical shell, two opposite end plates closing the ends of the cylindrical shell; said ports being provided through said shell; wherein the plug means comprises rotatable shaft means and baffle means mounted on said shaft means for rotation therewith; said baffle means closing off part of the interior of said shell from the remainder of the interior of said shell, said port and said remainder of the interior of said shell constituting said port-interconnecting passageway means.

3. The liquid pulsating device of claim 1 wherein the conduit means communicating the valve with the liquid in the column is exposed to the shell near one end thereof wherein the other two above-mentioned conduit means are exposed to the shell centrally of the shell, and wherein the shell is provided with two angularly spaced ports in registry with the exposure of the two last-mentioned conduit means to the shell; wherein the baffle means is constituted by plate means disposed across the interior of the shell generally centrally thereof so that one said two ports communicates with said part of the interior of the shell on one side of the baffle and the other of said two ports communicates with said remainder of the shell on the opposite side of the baffle.

4. The liquid pulsating device of claim 3 wherein the baffle plate means is constituted by an elliptical plate.

5. The liquid pulsating device of claim 3 wherein the baffle plate means is constituted by two complementary, radially extending semi-circular plates which are axially displaced from one another with respect to the longitudinal axis of the shaft means; and an axially extending plate connecting between the bases of the two semi-circular plates.

6. The liquid pulsating device of claim 3 wherein the baffle plate means is provided with curved plate means adjacent the opposite outer extents thereof for easing transition between communication and non-communication of each side of the interior of the shell with said ports.

7. The liquid pulsating device of claim 1 equipped for concurrent use with a second liquid-containing column, by further comprising:

conduit means for communicating the valve with the liquid in the second column;

the rotary valve port means including a further port communicable with said port-interconnecting passageway means for communicating the liquid in the second column with the source of suction while the liquid in the first column is being communicated, by said port-interconnecting passageway means, with the source of pressure, and for communicating the liquid in the second column with the source of pressure while the liquid in the first column is being communicated, by said port-interconnecting passageway means, with the source of suction.

8. The liquid pulsating device of claim 7 further including surge tank means interposed in the conduit means for communicating the valve with the liquid in at least one of the columns.

9. The liquid pulsating device of claim 1 wherein said conduit means for communicating the valve with the liquid in the column is disposed for connection to the bottom of the column and wherein the device further comprises:

conduit means for communicating the valve with the top of the column;

the rotary valve port means including a further port communicable with said port-interconnecting passageway means for communicating the top of the column with the source of suction while the bottom of the column is being communicated, by said port-interconnecting passageway means, with the source of pressure, and for communicating the top of the column with the source of pressure while the bottom is being communicated, by said port-interconnecting passageway means, with the source of suction.

10. The liquid pulsating device of claim 1 wherein the source of suction and the source of pressure are constituted by the suction and pressure sides, respectively, of a fluid pump.

11. A device for pulsating liquid in a column comprising:

a source of suction;

a source of pressure;

a first rotary valve means;

a second rotary valve means;

conduit means for communicating the first rotary valve means with the liquid in the column and for communicating the second rotary valve means with the liquid in the column;

first additional conduit means for communicating the first rotary valve means with the source of suction;

second additional conduit means for communicating the second rotary valve means with the source of pressure;

said first rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for communicating the liquid in the column with the source of suction when the port-interconnecting passageway means is aligned between the port means of said first rotary valve means and for terminating this communication when said port-interconnecting passageway means are not aligned between the port means of said first rotary valve means;

said second rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for communicating the liquid in the column with the source of pressure when the port-interconnecting passageway means is aligned between the port means of said second rotary valve means and for terminating this communication when said port-interconnecting passageway means are not aligned between the port means of said second rotary valve means; and

means for rotating the first and second rotary valve means plug means coordinately so that when one is communicating as recited, the other is not communicating as recited and vice versa.

12. The liquid pulsating device of claim 11, further including:

a surge vessel interposed in the first additional conduit means intermediate the first rotary valve means and the source of suction; and

a surge vessel interposed in the second additional conduit means intermediate the second rotary valve means and the source of pressure.

13. The liquid pulsating device of claim 11 wherein the first and second rotary valve means are coordinated by means mechanically coupling the respective plug means thereof.

14. The liquid pulsating device of claim 13 wherein the two plug means are coaxially disposed.

15. The liquid pulsating device of claim 14 wherein the mechanical coupling means is constituted by drive shaft means in common between the two plug means; and

wherein the conduit means first recited is constituted by a conduit having one end communicated to both plug means and having the other end thereof disposed for connection to the column.

16. The liquid pulsating device of claim 15 wherein the drive shaft means is vertically disposed and said conduit is disposed coaxially with said drive shaft means.

17. The liquid pulsating device of claim 11 wherein the port-interconnecting means of the plug means are so diametrically duplicated and disposed that for each complete rotation of the plug means each recited communicating and termination of communication is accomplished twice.

18. A device for pulsating liquid in a column comprising:

a source of suction;

a source of pressure;

rotary Valve means;

conduit means for communicating the valve means with the liquid in the column;

conduit means connecting the valve means with the source of suction;

conduit means connecting the valve means with the source of pressure;

said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for intermittently communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and

means for rotating said rotary valve means plug means.

19. Apparatus for treating liquids comprising:

a column;

a device for pulsating liquid in the column, including:

a source of suction;

a source of pressure;

rotary valve means;

conduit means communicating the valve means with the liquid in the column;

conduit means connecting the valve means with he source of suction;

conduit means connecting the valve means with the source of pressure;

said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means alternately communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and

means for rotating said rotary valve means plug means.

20. The apparatus of claim 19 wherein the claim is more than one meter in diameter. 

1. A device for pulsating liquid in a column comprising: a source of suction; a source of pressure; rotary valve means; conduit means for communicating the valve means with the liquid in the column; conduit means connecting the valve means with the source of suction; conduit means connecting the valve means with the source of pressure; said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway meaNs for alternately communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and means for rotating said rotary valve means plug means.
 1. A device for pulsating liquid in a column comprising: a source of suction; a source of pressure; rotary valve means; conduit means for communicating the valve means with the liquid in the column; conduit means connecting the valve means with the source of suction; conduit means connecting the valve means with the source of pressure; said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway meaNs for alternately communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and means for rotating said rotary valve means plug means.
 2. The liquid pulsating device of claim 1 wherein the valve comprises a housing including a cylindrical shell, two opposite end plates closing the ends of the cylindrical shell; said ports being provided through said shell; wherein the plug means comprises rotatable shaft means and baffle means mounted on said shaft means for rotation therewith; said baffle means closing off part of the interior of said shell from the remainder of the interior of said shell, said port and said remainder of the interior of said shell constituting said port-interconnecting passageway means.
 3. The liquid pulsating device of claim 1 wherein the conduit means communicating the valve with the liquid in the column is exposed to the shell near one end thereof wherein the other two above-mentioned conduit means are exposed to the shell centrally of the shell, and wherein the shell is provided with two angularly spaced ports in registry with the exposure of the two last-mentioned conduit means to the shell; wherein the baffle means is constituted by plate means disposed across the interior of the shell generally centrally thereof so that one said two ports communicates with said part of the interior of the shell on one side of the baffle and the other of said two ports communicates with said remainder of the shell on the opposite side of the baffle.
 4. The liquid pulsating device of claim 3 wherein the baffle plate means is constituted by an elliptical plate.
 5. The liquid pulsating device of claim 3 wherein the baffle plate means is constituted by two complementary, radially extending semi-circular plates which are axially displaced from one another with respect to the longitudinal axis of the shaft means; and an axially extending plate connecting between the bases of the two semi-circular plates.
 6. The liquid pulsating device of claim 3 wherein the baffle plate means is provided with curved plate means adjacent the opposite outer extents thereof for easing transition between communication and non-communication of each side of the interior of the shell with said ports.
 7. The liquid pulsating device of claim 1 equipped for concurrent use with a second liquid-containing column, by further comprising: conduit means for communicating the valve with the liquid in the second column; the rotary valve port means including a further port communicable with said port-interconnecting passageway means for communicating the liquid in the second column with the source of suction while the liquid in the first column is being communicated, by said port-interconnecting passageway means, with the source of pressure, and for communicating the liquid in the second column with the source of pressure while the liquid in the first column is being communicated, by said port-interconnecting passageway means, with the source of suction.
 8. The liquid pulsating device of claim 7 further including surge tank means interposed in the conduit means for communicating the valve with the liquid in at least one of the columns.
 9. The liquid pulsating device of claim 1 wherein said conduit means for communicating the valve with the liquid in the column is disposed for connection to the bottom of the column and wherein the device further comprises: conduit means for communicating the valve with the top of the column; the rotary valve port means including a further port communicable with said port-interconnecting passageway means for communicating the top of the column with the source of suction while the bottom of the column is being communicated, by said port-interconnecting passageway means, with the source of pressure, and for communicating the top of the column with the source of pressure while the bottom is being communicated, by said port-interconnecting passageway means, with tHe source of suction.
 10. The liquid pulsating device of claim 1 wherein the source of suction and the source of pressure are constituted by the suction and pressure sides, respectively, of a fluid pump.
 11. A device for pulsating liquid in a column comprising: a source of suction; a source of pressure; a first rotary valve means; a second rotary valve means; conduit means for communicating the first rotary valve means with the liquid in the column and for communicating the second rotary valve means with the liquid in the column; first additional conduit means for communicating the first rotary valve means with the source of suction; second additional conduit means for communicating the second rotary valve means with the source of pressure; said first rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for communicating the liquid in the column with the source of suction when the port-interconnecting passageway means is aligned between the port means of said first rotary valve means and for terminating this communication when said port-interconnecting passageway means are not aligned between the port means of said first rotary valve means; said second rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for communicating the liquid in the column with the source of pressure when the port-interconnecting passageway means is aligned between the port means of said second rotary valve means and for terminating this communication when said port-interconnecting passageway means are not aligned between the port means of said second rotary valve means; and means for rotating the first and second rotary valve means plug means coordinately so that when one is communicating as recited, the other is not communicating as recited and vice versa.
 12. The liquid pulsating device of claim 11, further including: a surge vessel interposed in the first additional conduit means intermediate the first rotary valve means and the source of suction; and a surge vessel interposed in the second additional conduit means intermediate the second rotary valve means and the source of pressure.
 13. The liquid pulsating device of claim 11 wherein the first and second rotary valve means are coordinated by means mechanically coupling the respective plug means thereof.
 14. The liquid pulsating device of claim 13 wherein the two plug means are coaxially disposed.
 15. The liquid pulsating device of claim 14 wherein the mechanical coupling means is constituted by drive shaft means in common between the two plug means; and wherein the conduit means first recited is constituted by a conduit having one end communicated to both plug means and having the other end thereof disposed for connection to the column.
 16. The liquid pulsating device of claim 15 wherein the drive shaft means is vertically disposed and said conduit is disposed coaxially with said drive shaft means.
 17. The liquid pulsating device of claim 11 wherein the port-interconnecting means of the plug means are so diametrically duplicated and disposed that for each complete rotation of the plug means each recited communicating and termination of communication is accomplished twice.
 18. A device for pulsating liquid in a column comprising: a source of suction; a source of pressure; rotary Valve means; conduit means for communicating the valve means with the liquid in the column; conduit means connecting the valve means with the source of suction; conduit means connecting the valve means with the source of pressure; said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means for intermittently communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and means for rotating Said rotary valve means plug means.
 19. Apparatus for treating liquids comprising: a column; a device for pulsating liquid in the column, including: a source of suction; a source of pressure; rotary valve means; conduit means communicating the valve means with the liquid in the column; conduit means connecting the valve means with he source of suction; conduit means connecting the valve means with the source of pressure; said rotary valve means having port means and a rotatable plug means provided with port-interconnecting passageway means alternately communicating the liquid in the column with the source of suction and with the source of pressure as the plug means is rotated; and means for rotating said rotary valve means plug means. 